Previous implementation only instantiated it on the front-end, which means e-mails sent from the back-end Order Actions metabox will not have structured data in them.
To provide a way for callbacks to modify the actual instance of the
variable product being sync'd, especially before its saved, in case
it needs to sync some meta data or other prop that can be set on the
object itself.
Because only a product ID is passed to callbacks on 'woocommerce_variable_product_sync',
they will need to instantiate their own instance of the product to do anything useful
with it. This creates a lot of potential for problems given that the product has at that
stage had its data sync'd but not all of it saved. For example, a callback may modify some
meta data on its own instance of the product, then save that, only to immediately have
that overridden if the instance of $product in WC_Product_Variable::sync() also had changes
to that meta data.
Instead, trigger 'woocommerce_variable_product_sync' only after the product has been
saved. This is backward compatible because the hook was triggered at the very end of
the process in WC < 2.7.
When SHA: 7b3a9b introduced wc_get_email_order_items(), it slightly
changed the logic applied to determine whether to display:
* download links; and
* purchase notes.
In WC 2.6.13 and older, WC_Abstract_Order::email_order_items_table()
would only display download links and purchase note in emails *not*
sent to the admin. This patch preserves that behaviour.
Rather than requiring child classes to merge it as well as define it.
If it's not defined in a child class, then the merge call will have no
effect as it will be an the empty array set in WC_Data, if they do define
it, WC_Data will now take care of it automatically rather than requiring
manually merging it in the child class's constructor before it has any
effect on that objects data.
This helps reduce duplicate code by removing this from child classes, and
in some cases, being able to remove the child constructor definitions
entirely. It also avoids a gotcha for developers setting their own
$extra_data values only to find they aren't being set on the $data
property.
Mike Jolley
Claudiu Lodromanean
divadmts
Boro Sitnikovski
Jaydeep
Brent Shepherd
Claudio Sanches
Caleb Burks